1. Field of the Invention
The present invention relates to an antenna driving apparatus and method in a wireless communication device, particularly to a method and apparatus for automatically driving an antenna of a wireless telephone with a sliding-embedded type antenna in which, by driving a motor, at the start of communication the antenna is automatically extended from an antenna housing, and reversely at the end of communication automatically retracted into the antenna housing.
2. Description of the Prior Art
Nowadays, generally a conventional wireless telephone, for example a cellular phone, a city phone, personal communication system (PCS) or the like, adopts a sliding-embedded type of antenna. A study teaches us that the intensity of electro-magnetic wave radiated when we use a wireless phone in a state of an antenna being fully extracted from an antenna housing is 1/3 as high as when we use the wireless phone in a state of the antenna being fully embedded in the antenna housing. Accordingly, using a wireless phone in the state that the antenna is fully extracted from the antenna housing, reduces the harm which may occur in a user's health due to the electro-magnetic wave radiated from the antenna.
Today, we can even find some conventional wireless telephones adopting a manually driven type of antenna in which a user himself manually extends or retracts an antenna from/into an antenna housing at the start or end of communication, respectively. But, to avoid this inconvenience, some other wireless phones adopting an automatic antenna extension/retraction system are disclosed.
An automatic antenna driving technique, U.S. Pat. No. 5,497,506 issued to Shinji Takeyasu, is disclosed. In order to overcome a problem of a prior art which adopts a spring-loaded type antenna where the antenna can be extracted by pressing a button from an antenna housing but a user should manually push the antenna into the antenna housing for retraction of the antenna, Shinji Takeyasu's patent suggests an antenna operating apparatus which comprises three operation switches of "OFF", "STANDBY" and "TALK" for antenna movement, wherein the antenna is extracted when "TALK" is selected and retracted when "STANDBY" is selected.
However, in this antenna moving mechanism, since a screw rod on which a nut is formed should be mounted on a motor shaft, a nut should be formed at the bottom of the antenna, and the antenna is vertically extracted and retracted by means of both engaged rotating nuts, a dedicated antenna is necessary for this moving mechanism. This generates a new problem of incompatibility with a currently used conventional wireless telephones. In addition, there is no solution for troubles caused by a deformation or a bending of the antenna due to an external disturbing force which may be frequently applied during antenna movement or during long-term usage, and it has some problems in system durability and stability of system operation.